Control Neopixel with Pure Data

giuliomoro

That's great news, thanks for coming back to us with your findings. The turn-on time is 2 orders of magnitude smaller than the rising time you are seeing, so it shouldn't be the main culprit here. To fix those smoothed edges I'd try adding a ceramic capacitor (100n or more) between 3.3V and GND very close to the 2N7000.

minovski

Hi @giuliomoro - in case analog I/O isn't needed, is it enough to just disable that from the project settings and then update main.cpp of O2L with PinmuxUtils::set("P9_18", "spi") to use the BBB SPI0 without having to bend pins?

giuliomoro

yes that should work. However, I recommend you check out the "pixelbone" branch. That one uses P8.35 without sacrificing neither the analogs nor the audio ins.

minovski

giuliomoro It seems the BelaArduino library is missing, is that some custom port of the Arduino headers for Bela, similar to RasPiArduino? Also, is it still necessary to load the device tree overlay with the pixelbone version?

giuliomoro

Try the latest commit from that branch, which removes that dependency.

carsten

giuliomoro Would you please elaborate a bit on how to use the pixelbone branch? For context im using ws2812b and was able to install O2L and setup program as service but was not able to test. I tried both example files and nothing happened, is P8.35 one below analogue input row? I intend to work in wiring as im not fimilar with pd or supercollider, would you pls share some insight on how that will work. Thanks

giuliomoro

You can see it here, you have to count pins from the edge. Trying to align it to the analog headers is error-prone.

With the correct pin, just run the project, download the patch local.pd to your computer and run it with Pd. That will use your computer's microphone to make a vumeter and send OSC to the board, which will translate them to the neopixel.

insultcomicdog

I'm trying to control a 24 led Neopixel ring with Bela:

https://www.adafruit.com/product/1586?srsltid=AfmBOorTx_oxKOI7n6kiWk4kiolJ37X8mJG-RykPCRYHf4lI6020Xkyw

I've updated my Bela board to dev:

https://github.com/BelaPlatform/Bela/tree/dev

For my neopixel ring I'm powering it with an external 5v PSU, and have shared the ground with the Bela.

The signal pin I'm using on Bela is P8.35.

Do I need to edit this line?

PinmuxUtils::set("P9_30", "spi"); // works on Bela, prints error on BelaMini

PinmuxUtils::set("P8_35", "spi"); // works on Bela, prints error on BelaMini

In the 02L app (https://github.com/giuliomoro/O2L) to get the PD example to work? My preference would be the control the ring without any hardware modifications and wanted to make sure this is the best method to achieve this.

giuliomoro

Use the pixelbone branch of O2L. Then you will have the signal on P8.35 on the BBB without hardware mods.

insultcomicdog

giuliomoro Thanks for the quick reply.

I was looking at the main branch previously and not pixelbone....I was able to download pixelbone, made a new C++ project in the Bela IDE. Do I need to delete 'render.cpp'?

I uploaded all the project files and ran it in the IDE.

I got this message in console:

I think I need to modify block size in project settings in the IDE currently set to 16. What should it be set to?

I ran 'local.pd' in PD on my mac. Turned audio on and I can see the VU meter moving in PD when I speak into mic but not activity from neopixel ring.

I checked the above pin diagram. The signal pin I'm using is 6 pins up from the bottom right.

giuliomoro

Sorry for the late reply.

I cannot reproduce the error you are seeing, but it's been reported elsewhere and the solution is to remove the file run.sh from the project folder. Build and run the project, it should print

pru_init: PRU 0: data 0xb6bdf000 @ 8192 bytes,  DMA 0xb6b5f000 / 9f700000 @ 262144 bytes

Then the local.pd script should work on the host as expected. When you verify this works as expected, run these two commands in the console at the bottom of the IDE

cp /root/Bela/projects/O2L/O2L.service /lib/systemd/system/
systemctl enable O2L && systemctl start O2L

to install it and run it in the background so that you can run another Bela project alongside it.

insultcomicdog

@giuliomoro Thank you! Deleting run.sh fixed compiling the pixelbone branch of O2L.

I was able to get the local.pd script working, and run O2L in the background while running another PD project on Bela, and the O2L service is also running on boot.

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